While riding their motorcycles into town, Frank and Joe Hardy are nearly run off the road by a roadster that they later realize belongs to their friend Chet. As they set out to solve the mystery of the stolen car, the tower mansion is broken into and robbed. Are the crimes related? The Hardy boys will do their best to figure it out.

This book is the first in the Hardy boys series of novels, first published in 1927. It was updated and rewritten in 1959, but this Standard Ebooks edition follows the first edition text.